The present invention is directed to processes for seaming components useful in electrostatographic, including digital, apparatuses. In specific embodiments, the present invention is directed to seaming processes useful for components such as seamed belts, and more specifically, to endless flexible seamed belts wherein an image can be transferred at the seam of the belt with little or no print defects caused by the seam. In embodiments, the present invention relates to processes for seaming xerographic component imagable seamed belts, wherein an adhesive is formed between mutually mating elements of a seam. In embodiments, the process includes two curing steps, and in preferred embodiments, the second cure is at a temperature higher than that of the first cure step. In embodiments, the seam is bonded using a first clamp and a second clamp, wherein the clamps may be heated. In an embodiment, the adhesive between seaming members comprises a resin, such as a hot-melt processable, thermosetting resin, preferably containing electrically conductive filler(s) dispersed or contained therein.
The seam produced by the process herein is strong enough to survive mechanical flexing while under tension, as the belt travels over various diameter rollers. The process herein, in embodiments, provides a seam in which the height differential between the seam and the rest of the belt is virtually nil. The process herein, in embodiments, provides a belt allowing for image transfer at the seam, which cannot be accomplished with known seamed belts. Image transfer is accomplished partly because the process provides a seam that possesses the desired conductivity and release properties required for sufficient transfer. Image transfer is further made possible because the process provides a seam that is virtually or completely free of bubbles, voids, and other inclusions, which may impact high quality image transfer at the seam region and/or reduce the mechanical strength of the seam. The process provides crosslinking of the adhesive into a strong, solid phase interface having the desired conductivity and release properties to function as an imagable seam. The present process, in embodiments, is further easy to control and low cost.
In a typical electrostatographic reproducing apparatus such as an electrophotographic imaging system using a photosensitive member, a light image of an original to be copied is recorded in the form of an electrostatic latent image upon a photosensitive member and the latent image is subsequently rendered visible by the application of a developer mixture. One type of developer used in such printing machines is a liquid developer comprising a liquid carrier having toner particles dispersed therein. Generally, the toner is made up of resin and a suitable colorant such as a dye or pigment. Conventional charge director compounds may also be present. The liquid developer material is brought into contact with the electrostatic latent image and the colored toner particles are deposited thereon in image configuration.
The developed toner image recorded on the imaging member is transferred to an image receiving substrate such as paper via a transfer member. The toner particles may be transferred by heat and/or pressure to a transfer member, or more commonly, the toner image particles may be electrostatically transferred to the transfer member by means of an electrical potential between the imaging member and the transfer member. After the toner has been transferred to the transfer member, it is then transferred to the image receiving substrate, for example by contacting the substrate with the toner image on the transfer member under heat and/or pressure.
Transfer members enable high throughput at modest process speeds. In four-color photocopier or printer systems, the transfer member also improves registration of the final color toner image. In such systems, the four component colors of cyan, yellow, magenta and black may be synchronously developed onto one or more imaging members and transferred in registration onto a transfer member at a transfer station.
In electrostatographic printing and photocopy machines in which the toner image is transferred from the transfer member to the image receiving substrate, it is desired that the transfer of the toner particles from the transfer member to the image receiving substrate be substantially 100 percent. Less than complete transfer to the image receiving substrate results in image degradation and low resolution. Complete transfer is particularly desirable when the imaging process involves generating full color images since undesirable color deterioration in the final colors can occur when the color images are not completely transferred from the transfer member.
Thus, it is desirable that the transfer member surface has excellent release characteristics with respect to the toner particles. Conventional materials known in the art for use as transfer members often possess the strength, conformability and electrical conductivity necessary for use as transfer members, but can suffer from poor toner release characteristics, especially with respect to higher gloss image receiving substrates.
Polyimide substrate transfer members are suitable for high performance applications because of their outstanding mechanical strength and thermal stability, in addition to their good resistance to a wide range of chemicals. However, the high cost of manufacturing unseamed polyimide belts has led to the introduction of a seamed belt.
In the electrostatic transfer applications, use of a seamed transfer polyimide member made by conventional seaming processes results in insufficient transfer in that the developed image occurring on the seam is not adequately transferred. This incomplete transfer is partially the result of the difference in seam height and the rest of the belt. A xe2x80x9cbumpxe2x80x9d is formed at the seam, thereby hindering transfer and mechanical performance. The development of puzzle cut seams has increased the quality of transfer somewhat, by decreasing the seam height, thereby allowing smooth mechanical cycling. However, even with the improvements made with puzzle cut seams, quality imaging in the seamed area is not obtainable at present due, in part, to contrast in transfer caused by differences in electrical and release properties of known seaming adhesives and known seaming processes. Further, current seaming processes do not provide sufficient bonding strength at the seam, resulting in short belt life. In addition, the seam must have the appropriate surface properties in order to allow for sufficient toner release at the seam.
Currently, seam adhesives consist of insulating ultraviolet-curable epoxies and hot-melt adhesives. Present seaming processes consist of the use of ultraviolet light to cure the epoxy adhesives or heat and pressure to thermally cure the hot melt adhesives or heat and pressure to thermally bond or xe2x80x9cweldxe2x80x9d the seam. While these adhesives and related processes produce seamed belts that exhibit acceptable strengths at room temperature under tensile load, most undergo premature failure at elevated temperatures. Additionally, belts made by existing seaming processes have been found to perform poorly under some important dynamic test conditions.
Therefore, it is desired to provide a process which produces a more robust seam for puzzle cut and other types of seamed belts. Further, it is desired to provide a process for producing a seam having electrical, mechanical and toner release characteristics that closely match those of the robust substrates. In addition, it is desirable to provide a process for producing a seam which is imagable, thereby reducing or eliminating the presence of print or copy defects. Also, it is desired to provide a process for producing a seam in which the height differential between the seam and the rest of the belt is virtually nil. Moreover, it is further desired to provide a process for producing a seam that is virtually or completely free of bubbles, voids and other inclusions, which may impact high quality image transfer or strength of the seam region. It is further desirable to provide a process that is easy to control and low cost.
U.S. Pat. No. 5,549,193 relates to an endless flexible seamed belt comprising puzzle cut members, wherein at least one receptacle has a substantial depth in a portion of the belt material at the belt ends.
U.S. Pat. No. 5,721,032 discloses a puzzle cut seamed belt having a strength-enhancing strip.
U.S. Pat. No. 5,487,707 discloses a puzzle cut seamed belt having a bond between adjacent surfaces, wherein an ultraviolet cured adhesive is used to bond the adjacent surfaces.
U.S. Pat. No. 5,514,436 relates to a puzzle cut seamed belt having a mechanically invisible seam, which is substantially equivalent in performance to a seamless belt.
U.S. Pat. No. 6,318,223 discloses a process and apparatus for producing an endless seamed flexible belt.
U.S. Pat. No. 6,316,070 discloses unsaturated carbonate adhesives for component seams.
U.S. Pat. No. 6,379,486 discloses process for seaming interlocking seams of polymide component using polyimide adhesive.
U.S. Pat. No. 6,327,454 discloses imageable seamed belts having fluoropolymer adhesives between interlocking seaming members.
U.S. Pat. No. 6,387,465 discloses imageable seamed belts having fluoropolymer overcoat.
U.S. Pat. No. 6,527,105 discloses imageable seamed belts having hot melt processable, thermosetting resin and conductive filler adhesive between interlocking seaming members.
Embodiments of the present invention include: A process for seaming a film component, wherein the film component comprises a seam having a first side and a second side and said seam comprising mutually mating members, wherein the process comprises: a) compounding an adhesive; b) forming the adhesive in contact with the first side of the seam and the mutually mating members; c) contacting the adhesive and first side of the seam to a first heated clamp; d) contacting the second side of the seam to a second heated clamp; e) subjecting the adhesive in contact with the mutually mating members to a first cure at a first temperature to form a cured adhesive; and f) subjecting the cured adhesive to a second cure at a second temperature to form a dual-cured adhesive, wherein the second temperature is higher than the first temperature.
Embodiments of the present invention also include: a process for seaming a puzzle cut component, wherein the component comprises a puzzle cut seam having a first side and a second side, and the seam comprising mutually mating members, each member having a puzzle cut form, wherein the process comprises: a) compounding an adhesive; b) forming the adhesive in contact with the first side of the seam and in further contact with the puzzle cut mutually mating members; c) contacting the adhesive and first side of the seam to a first heated clamp; d) contacting the second side of the seam to a second heated clamp; e) subjecting the adhesive in contact with the mutually mating members to a first cure at a first temperature to form a cured adhesive; and f) subjecting the cured adhesive to a second cure at a second temperature to form a dual-cured adhesive, wherein the second temperature is higher than the first temperature.
Embodiments further include: a process for seaming a film component, wherein the film component comprises a seam having a first side and a second side and comprising mutually mating members, wherein the process comprises: a) compounding an adhesive comprising a hot-melt processable, thermosetting resin and an electrically conductive filler; b) forming the adhesive in contact with the first side of the seam and the mutually mating members; c) contacting the adhesive and first side of the seam to a first heated clamp; d) contacting the second side of the seam to a second heated clamp; e) subjecting the adhesive in contact with the mutually mating members to a first cure at a first temperature to form a cured adhesive; and f) subjecting the cured adhesive to a second cure at a second temperature to form a dual-cured adhesive, wherein the second temperature is higher than the first temperature.